1. Field of the Invention
The present invention relates to a final gear mechanism for a motorcycle. More particularly, the present invention relates a motorcycle in which a final gear transmission mechanism is interposed between a drive shaft and a rear wheel.
2. Description of the Background Art
There is known a motorcycle in which a final gear transmission mechanism for transmitting a rotary drive force of an engine is interposed between a drive shaft and a rear wheel. An example of such final gear transmission mechanism is disclosed in the Japanese Utility Model publication No. 2-393 (see FIG. 5 thereof).
According to the Japanese Utility Model publication No. 2-393, as shown in FIG. 5 thereof, the final gear transmission mechanism includes a pinion gear 3 (same reference numbers are used here as they are in the cited document), a ring gear 4 meshed with the pinion gear 3, a cylindrical sleeve attached with the ring gear 4, and provided for rotation around a rear axle 24, and a rear wheel 6 integrally joined to the cylindrical sleeve. The drive force of the pinion gear 3 is transmitted to the rear wheel 6.
Incidentally, according to the Japanese Utility Model publication No. 2-393, the sleeve attached with the ring gear 4 is inserted into the rear axle 24 in the axial direction thereof toward the rear wheel 6. The sleeve is a member permitted to slightly move in the axial direction of the rear axle 24.
When the sleeve is axially movable, the ring gear 4 integrally attached to the sleeve is axially moved along with the movement of the sleeve. This disadvantageously varies the meshing state between the ring gear 4 and the pinion gear 3, which may probably cause e.g. gear noise. Therefore, it is desirable to improve the final gear transmission mechanism for achieving desired, stabilized meshing state between a ring gear and a pinion gear of the final transmission mechanism.
The present invention has been made to overcome such drawbacks of the existing final gear transmission mechanism. Accordingly, it is one of the objects of the present invention to provide a motorcycle including a final gear transmission mechanism having increased fastening rigidity of a rear axle attached with a ring gear in order to stabilize a meshing state between a ring gear and a pinion gear meshed with the ring gear.